The present invention relates to a folded-seam connection and to a method of producing it, as well as to a device for performing the method.
Folded-seam connections are well known in ventilation and air-conditioning technology. These connections have the inherent drawback that they are not tight, since after it has been produced any folded-seam connection will tend to spring back, i.e. to open. The resulting leakage losses of connections of this type, however, are frequently unacceptable on the grounds of hygiene, health and/or energy, so additional action is necessary for sealing, for example for inserting a strip of rubber and/or for securing the folded-seam connection by adhesion; cf. inter alia WO 00/27557, FIGS. 10 to 13, in which various ways in which to clamp seals are illustrated.
This leads to further drawbacks: As well as the resulting high outlay in materials and time for introducing additional sealing material into the folded-seam connection its effectiveness is substantially dependent upon the carefulness of the user (worker). In addition, even synthetic sealing materials tend to become brittle and withstand only slight differences in pressure, in particular if relatively large gaps and/or shearing forces are involved.